/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.net.netlink;
import static android.net.netlink.StructNlMsgHdr.NLM_F_ACK;
import static android.net.netlink.StructNlMsgHdr.NLM_F_DUMP;
import static android.net.netlink.StructNlMsgHdr.NLM_F_REPLACE;
import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
import android.net.netlink.StructNdaCacheInfo;
import android.net.netlink.StructNdMsg;
import android.net.netlink.StructNlAttr;
import android.net.netlink.StructNlMsgHdr;
import android.net.netlink.NetlinkMessage;
import android.system.OsConstants;
import android.util.Log;
import java.net.InetAddress;
import java.net.Inet6Address;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
/**
* A NetlinkMessage subclass for netlink error messages.
*
* see also: <linux_src>/include/uapi/linux/neighbour.h
*
* @hide
*/
public class RtNetlinkNeighborMessage extends NetlinkMessage {
public static final short NDA_UNSPEC = 0;
public static final short NDA_DST = 1;
public static final short NDA_LLADDR = 2;
public static final short NDA_CACHEINFO = 3;
public static final short NDA_PROBES = 4;
public static final short NDA_VLAN = 5;
public static final short NDA_PORT = 6;
public static final short NDA_VNI = 7;
public static final short NDA_IFINDEX = 8;
public static final short NDA_MASTER = 9;
private static StructNlAttr findNextAttrOfType(short attrType, ByteBuffer byteBuffer) {
while (byteBuffer != null && byteBuffer.remaining() > 0) {
final StructNlAttr nlAttr = StructNlAttr.peek(byteBuffer);
if (nlAttr == null) {
break;
}
if (nlAttr.nla_type == attrType) {
return StructNlAttr.parse(byteBuffer);
}
if (byteBuffer.remaining() < nlAttr.getAlignedLength()) {
break;
}
byteBuffer.position(byteBuffer.position() + nlAttr.getAlignedLength());
}
return null;
}
public static RtNetlinkNeighborMessage parse(StructNlMsgHdr header, ByteBuffer byteBuffer) {
final RtNetlinkNeighborMessage neighMsg = new RtNetlinkNeighborMessage(header);
neighMsg.mNdmsg = StructNdMsg.parse(byteBuffer);
if (neighMsg.mNdmsg == null) {
return null;
}
// Some of these are message-type dependent, and not always present.
final int baseOffset = byteBuffer.position();
StructNlAttr nlAttr = findNextAttrOfType(NDA_DST, byteBuffer);
if (nlAttr != null) {
neighMsg.mDestination = nlAttr.getValueAsInetAddress();
}
byteBuffer.position(baseOffset);
nlAttr = findNextAttrOfType(NDA_LLADDR, byteBuffer);
if (nlAttr != null) {
neighMsg.mLinkLayerAddr = nlAttr.nla_value;
}
byteBuffer.position(baseOffset);
nlAttr = findNextAttrOfType(NDA_PROBES, byteBuffer);
if (nlAttr != null) {
neighMsg.mNumProbes = nlAttr.getValueAsInt(0);
}
byteBuffer.position(baseOffset);
nlAttr = findNextAttrOfType(NDA_CACHEINFO, byteBuffer);
if (nlAttr != null) {
neighMsg.mCacheInfo = StructNdaCacheInfo.parse(nlAttr.getValueAsByteBuffer());
}
final int kMinConsumed = StructNlMsgHdr.STRUCT_SIZE + StructNdMsg.STRUCT_SIZE;
final int kAdditionalSpace = NetlinkConstants.alignedLengthOf(
neighMsg.mHeader.nlmsg_len - kMinConsumed);
if (byteBuffer.remaining() < kAdditionalSpace) {
byteBuffer.position(byteBuffer.limit());
} else {
byteBuffer.position(baseOffset + kAdditionalSpace);
}
return neighMsg;
}
/**
* A convenience method to create an RTM_GETNEIGH request message.
*/
public static byte[] newGetNeighborsRequest(int seqNo) {
final int length = StructNlMsgHdr.STRUCT_SIZE + StructNdMsg.STRUCT_SIZE;
final byte[] bytes = new byte[length];
final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
byteBuffer.order(ByteOrder.nativeOrder());
final StructNlMsgHdr nlmsghdr = new StructNlMsgHdr();
nlmsghdr.nlmsg_len = length;
nlmsghdr.nlmsg_type = NetlinkConstants.RTM_GETNEIGH;
nlmsghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
nlmsghdr.nlmsg_seq = seqNo;
nlmsghdr.pack(byteBuffer);
final StructNdMsg ndmsg = new StructNdMsg();
ndmsg.pack(byteBuffer);
return bytes;
}
/**
* A convenience method to create an RTM_NEWNEIGH message, to modify
* the kernel's state information for a specific neighbor.
*/
public static byte[] newNewNeighborMessage(
int seqNo, InetAddress ip, short nudState, int ifIndex, byte[] llAddr) {
final StructNlMsgHdr nlmsghdr = new StructNlMsgHdr();
nlmsghdr.nlmsg_type = NetlinkConstants.RTM_NEWNEIGH;
nlmsghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE;
nlmsghdr.nlmsg_seq = seqNo;
final RtNetlinkNeighborMessage msg = new RtNetlinkNeighborMessage(nlmsghdr);
msg.mNdmsg = new StructNdMsg();
msg.mNdmsg.ndm_family =
(byte) ((ip instanceof Inet6Address) ? OsConstants.AF_INET6 : OsConstants.AF_INET);
msg.mNdmsg.ndm_ifindex = ifIndex;
msg.mNdmsg.ndm_state = nudState;
msg.mDestination = ip;
msg.mLinkLayerAddr = llAddr; // might be null
final byte[] bytes = new byte[msg.getRequiredSpace()];
nlmsghdr.nlmsg_len = bytes.length;
final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
byteBuffer.order(ByteOrder.nativeOrder());
msg.pack(byteBuffer);
return bytes;
}
private StructNdMsg mNdmsg;
private InetAddress mDestination;
private byte[] mLinkLayerAddr;
private int mNumProbes;
private StructNdaCacheInfo mCacheInfo;
private RtNetlinkNeighborMessage(StructNlMsgHdr header) {
super(header);
mNdmsg = null;
mDestination = null;
mLinkLayerAddr = null;
mNumProbes = 0;
mCacheInfo = null;
}
public StructNdMsg getNdHeader() {
return mNdmsg;
}
public InetAddress getDestination() {
return mDestination;
}
public byte[] getLinkLayerAddress() {
return mLinkLayerAddr;
}
public int getProbes() {
return mNumProbes;
}
public StructNdaCacheInfo getCacheInfo() {
return mCacheInfo;
}
public int getRequiredSpace() {
int spaceRequired = StructNlMsgHdr.STRUCT_SIZE + StructNdMsg.STRUCT_SIZE;
if (mDestination != null) {
spaceRequired += NetlinkConstants.alignedLengthOf(
StructNlAttr.NLA_HEADERLEN + mDestination.getAddress().length);
}
if (mLinkLayerAddr != null) {
spaceRequired += NetlinkConstants.alignedLengthOf(
StructNlAttr.NLA_HEADERLEN + mLinkLayerAddr.length);
}
// Currently we don't write messages with NDA_PROBES nor NDA_CACHEINFO
// attributes appended. Fix later, if necessary.
return spaceRequired;
}
private static void packNlAttr(short nlType, byte[] nlValue, ByteBuffer byteBuffer) {
final StructNlAttr nlAttr = new StructNlAttr();
nlAttr.nla_type = nlType;
nlAttr.nla_value = nlValue;
nlAttr.nla_len = (short) (StructNlAttr.NLA_HEADERLEN + nlAttr.nla_value.length);
nlAttr.pack(byteBuffer);
}
public void pack(ByteBuffer byteBuffer) {
getHeader().pack(byteBuffer) ;
mNdmsg.pack(byteBuffer);
if (mDestination != null) {
packNlAttr(NDA_DST, mDestination.getAddress(), byteBuffer);
}
if (mLinkLayerAddr != null) {
packNlAttr(NDA_LLADDR, mLinkLayerAddr, byteBuffer);
}
}
@Override
public String toString() {
final String ipLiteral = (mDestination == null) ? "" : mDestination.getHostAddress();
return "RtNetlinkNeighborMessage{ "
+ "nlmsghdr{" + (mHeader == null ? "" : mHeader.toString()) + "}, "
+ "ndmsg{" + (mNdmsg == null ? "" : mNdmsg.toString()) + "}, "
+ "destination{" + ipLiteral + "} "
+ "linklayeraddr{" + NetlinkConstants.hexify(mLinkLayerAddr) + "} "
+ "probes{" + mNumProbes + "} "
+ "cacheinfo{" + (mCacheInfo == null ? "" : mCacheInfo.toString()) + "} "
+ "}";
}
}